Rising Batter

• Milk in cake batter serves two main purposes: to form a small amount of the protein gluten when mixed with flour; and to cause a chemical reaction with leavening agents, such as baking powder or baking soda. These two processes give off carbon dioxide and cause the cake to rise. Without the right amount of liquid added to the batter, cakes will not have a proper structure or the right texture. The right amount of milk added will leave you with a cake that's light and airy with tiny holes that are created when air bubbles caused by rising carbon dioxide levels turn to steam and escape.

Cake Texture

• Milk comprises approximately 87 percent water; 5 percent carbohydrate (lactose); and 8 percent milk solids, consisting of equal parts fat and protein. The naturally occurring fat in milk keeps cake crumbs tender rather than hard and chewy. Unlike water, milk contains lactose, a sugar that caramelizes at low temperatures and helps create a nicely toasted outer edge on the cake. In yellow cakes, it results in the golden color and crusty texture of the cake's surface.

Milk Substitutes

• Milk is a multifunctional ingredient in cakes. The proteins in milk -- primarily casein -- help bind all the ingredients together in cake batter, and the fat adds to the texture and flavor of the cake. Ideal substitutions for milk would have at least some protein and some fat. Soy milk is one of the best substitutes, because it is nutritionally similar to milk. Rice milk, coconut milk and almond milk can be used, but you may want to increase the fat in the recipe by 1 tablespoon per cup of these low-fat milk substitutes.

How to Use Milk

• When baking with milk, it's best to begin with the milk at room temperature. Milk at room temperature will combine more readily and bind with other ingredients to create an emulsion that will help trap the air bubbles that are formed when the liquids react with the leavening in the cake batter. This will result in a cake that will rise more evenly while baking. Take the milk out of the refrigerator 30 to 60 minutes before using it in your cake recipe, and make sure the eggs and butter are also at room temperature.